“The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth.” John 1:14
The Jewish people knew God’s promise to send a Messiah. They knew a human being couldn’t become God, but it hadn’t occurred to them that God would humble himself to such an extent as to become a human being. John wrote his account so we would know that Jesus is God in the flesh. “The one and only Son, who is himself God” (1:18, 20:31).